The arrest of leaders of criminal gangs in the wake of last year's riots has led to an increase in "chaos, violence and anarchy", a report has claimed.

Prime Minister David Cameron promised an "all-out war on gangs and gang culture" following the riots, which brought mayhem to some English cities in the summer of 2011.

Police then responded by arresting many of those associated with criminal groups.

But a report by the Centre for Social Justice, obtained by The Observer, found that the removal of established gang leaders has led to the breakdown of criminal codes of behaviour and a "marked increase" in violence.

The report said: "Many in Whitehall regard the riots as a random one-off, and mistake the quashing of the disorder as control of the streets. They could not be more wrong.

"The alarming fact is that many streets across the country are besieged by anarchy and violence. There is no control in such neighbourhoods."

Image Caption:David Cameron with police in Croydon after the riots

The report said people in riot-hit areas had reported a "marked increase" in the violent behaviour of some gangs because of the removal from the streets of "elders" who had previously imposed a code of behaviour.

"There was a consensus that the current gangs neither have such a code nor cohesive leadership, which is resulting in increased chaos, violence and anarchy," said the report.

Christian Guy, managing director of the CSJ, which was founded by Work and Pensions Secretary Iain Duncan Smith, said: "Gangs played a significant role in the riots and it is dangerous to pretend otherwise.

"In London, at least one in five of those convicted was part of a gang."

The CSJ report recommended "addressing the drivers of gang culture, not just the symptoms".

It said: "The surest way of eliminating gangs is to try to ensure that children and young people never want or feel the need to join them.

"To do this we need to tackle deeper issues in our society and seek to nurture and support ever-strong families and stronger communities."